\documentclass{ctexart}
\usepackage{amsmath}
\usepackage{hyperref}
\usepackage{tikz}

\newcommand{\partialyx}[2]{\frac{\partial #1}{\partial #2}}

\begin{document}

\input{modeling.tex}
\input{simulation.tex}
\input{linearization.tex}
\input{control.tex}
\input{doubleip.tex}

\end{document}
